Boundary layer control



Aug. 27, 1963 FRADENBURGH 3,101,920

BOUNDARY LAYER CONTROL Fii ed Jan. 27, 1960 2 Sheets-Sheet 1 INVENTOR EVAN A FRADENBURGH Aug. 27, 1963 I E. A. FRADENB-URGH 3,101,920

BOUNDARY LAYER CONTROL Filed Jan. 27, 1960 I 2 Sheets-Sheet 2 FIG-6 INVENTOR EVAN A- FRADENBURGH ag M AGENT tte BOUNDARY LAYER CONTRQL Evan A. Fradenhurgh, Fairfiel-rl, onn., assignor to United Aircraft Corporation, East Hartford, Conn, a corporation of Delaware Filed Jan. 27, 196i), SeraNo. 4,919 13 Claims. (Cl. 244-136) ice the fuselage. The usual main and auxiliary landing gear,

wardly from a point between the rotor head and pylon.

A further object of this invention is to provide a telescoping afterbody for a cylinder.

Another object of this invention is to provide means permitting relative rotation between a telescoping afterbody and the bottom of a fairing- A further object of this invention is to provide an air or gas control means for regulating the flow sent through any particular boundary layer control system nozzle.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

FIG. 1 is a side elevation of a helicopter embodying the invention;

FIG. 2 is an enlarged side view of the rotor head fairing showing the control system enclosure cylinder and cylinder telescoping afterbody;

FIG. 3 is a side view showing the rotor head fairing in a position which is tilted forwardly;

FIG. 4 is a perspective view of the control system en'- closure cylinder and cylinder telescoping after-body along with actuating means for controlling air or gas flow;

FIG. 5 is a cross-sectional view taken longitudinally through a nozzle of the control system enclosure cylinder;

FIG. 6 is a modification of the boundary layer control system shown in FIGS. 1 to 4;

FIG. 7 is an enlarged view taken along the line 77 of FIG. 6;

8 is another modification of a boundary layer control system;

, FIG. 9 is a view taken along the line 99 of FIG. 8; FIG. 10 is a sectional view of the rear end of the modification shown in FIG. 8;

FIG. 11 is another modification of a boundary layer control system;

FIG. 12 is a view taken along the line 12--12 of FIG. 11; and

FIG. l3 is a sectional view of the rear end of the modification shown in FIG. 11.

' Referring to FIG. 1, this figure shows a helicopter having a fuselage 10 including a cargo or passenger compartment 12 which extends from the nose of the ship aft into the tail cone 14. A pilots compartment 16 is located above the cargo or passenger compartment. A tail rotor pylon 18 is also provided having the usual anti-torque tail rotor20 mounted thereon for rotation. A main sustaining rotor 22 is mounted on an upright tubular shaft 32 and 34, are provided for supporting the ship on the ground.

' A rotor head 22 is mounted on a tubular shaft 24 and is shown without actuating means for the blades 27. Rotor heads and actuating systems which may be used are shown in US. Patent No. 2,638,994 and US. Patent No. 2,672,940. The rotor head fairing 100 is shown and claimed in US. application Serial No. 4920, now Patent No. 3,056,456, filed concurrently herewith for a Rotor Head Fairing by Philip L. Michel and Evan A. Fradenburgh.

A control system enclosure cylinder 50 extends from the pylon 26 upwardly towards the rotor head. In FIG. 2 this cylinder is shown extending into the fairing 100. A sealing means 51 is provided between the bottom of the fairing and the cylinder 50. This sealing means 51 comprises an annular disk 116 which is placed inside of the rotor head fairing with its inner circumference just fitting around the outer circumference of the control system enclosure cylinder. A plurality of springs 118 are spaced around the opening 114 provided'in the lower portion of the rotor head fairing. Each spring has one end fixed to the rotor head fairing while the free end exerts a pressure downwardly on the disk.

A plurality of nozzles 60 are located in the side wall of the cylinder and have their outlets directed rearwardly and substantially tangentially of the cylinder. Each nozzle is positioned in a cylindrical opening 62 drilled in the cylinder wall. The outlet 64 of each opening tapers inwardly at 66. These openings 62 are shown arranged in two vertical lines, one line being located on each side of the cylinder. Each line of jets could be located forwardly or rearwardly of the position shown, but the most efficient location would be slightly forward of the point where flow separation would normally occur.

A manifold system is used to direct air or gas to the nozzles 60. This manifold system comprises a semicircular portion 72 which extends around the inside of the upper portion of cylinder 50. A straight section 74 extends downwardly from each end of the semicircular por- 24 which extends from the'main rotor pylon 26 located tion72. A short conduit 76 extends from each straight portion 74 to each passageway 73 drilled through the inner wall of cylinder 50. Each passageway 78 is connected to its cooperating nozzle inlet by a passageway 30.

An air or gas supply 32 is connected to the semicircular portion 72 by a conduit 84. A variable output pump 86 is located in said conduit and controlled by a pilot actuated device 88. A flow indicating device 90 indicates to the pilot the total flow passing through conduit 84. The pilot can then control flow as desired.

A valve 92 is located in each short conduit 76 and is rn'oveable hy the pilot through an actuating device 94 and interconnecting mechanism 96. This permits the pilot to control the individual flow through any nozzle 6%, or combination of nozzles, of either line of nozzles.

A cylinder telescoping afterbody is provided to streamline the cylinder and extends from a point on each side of the cylinder just aft of the outlets 64 of the openings 62 to a midpoint rearwardly of the cylinder.

Af-terbody 150 comprises three main fairing sections. The first of these sections, section 152, is fixed with relation to cylinder 50 and pylon 26. Each forward end of this section 152 extends upwardly from the pylon on midpoint 154 from its respective front point with each side tapering upwardly. Thetwo sides of the section 152 3 are fixed where they meet at their rearward end and form a line which extends rearwardly from its top point 154 to its bottom point 156 forming a streamlined fairing. Each side where it meets, pylon 26 is located outward of a line directly under the top for a purpose to be hereinafter described.

The second section of the afterbody 150, section 158, comprises two side plates 16%. Each plate is positioned on the inside of each side of section 152 and extends for substantially its inner length. Each side plate 169 is pivoted at its upper rearward end, at point 162, to its cooperating side of section 152. This arrangement provides for rotation between each plate 160 about the pivot points 162.

The third section of the afterbody 150, section 164, comprises a fairing member having two sides 166 joined at their rearward ends by a pivot point 167. This permits rotation between each side 166 about pivot point 167. These members fit within the V-shape formed by the side plates 160 of the second section of the afterbody 150. This third section 164 has each side 166 pivoted at its forward end to its cooperating side plate 160 at point 168. When the rotor head fairing tilts to the side, the afterbody tilts also. The bottom of each plate 160 and side 166 is permitted movement sideways in view of the outward taper of the sides of section 152.

A spring member 170 is located on each inner side of the afterbody 150 and is fixed at its lower end at 172 to its respective side of the first section 152. Each spring has its other end located against a flange 174 which projects inwardly from the top of each side 166 of the third section 158 of the afterbody 150. The action of Spring 170 biases the cylinder telescoping afterbody to its expansive position and maintains the top edge of each of the sides 166 of the third section of the afterbody against the underportion of the fairing 100 in all positions.

A hearing unit is located Within the rearward end of the third section of the afterbody 150. This bearing unit comprises a ball member 180 mounted for movement within a socket member 132 fixed in position between plates 166. This member reduces friction between the rotor fairing 106i and the afterbody when there is relative rotation. This bearing unit also reduces friction between these two members when the fairing 100 is tilted with respect to the cylinder 50 and afterbody 150 (see FIG. 3). Other bearing units can be used between the fairing and afterbody if necessary.

FIGURES 6 and 7 show a modification of the boundary layer control system in which the plurality of nozzles 60 are replaced by a single manifold 200 with a rearwardly directed nozzle shaped slot 202. The conduit 84 directing the air or gas supply is connected directly to the bottom of the manifold 200. The manifold tapers in wardly from its bottom to the top and turning vanes 294 are provided so that an even flow distribution is maintained passing from the slot 202.

FIGURES 8 to 10 show a modification of the boundary layer control system in which air is drawn in from the rear of the cylinder 50 through an opening 300. The lower end of cylinder 50 is connected by a manifold 302 to a conduit 304. This conduit 304 can be directed to the inlet of a turbine engine or can be connected directly to a pump for creating a suction. A splitter plate 306 extends rearwardly from a point located midway in the opening 300. While this plate has been shown solid with the top cut away to provide for rotor fairing tilt, a simple telescoping splitter vane can be used if it is desired to have the plate 306 extend to a mating position with the fairing. Any actuating control rod or other mechanism which extends downwardly from the rotor head 22 in fairing 100 can be sealed with respect to the manifold 302 or any other portion of the ducting through which they may have to pass. The splitter plate divides the suction flow and establishes a stable symmetrical flow.

FIGURES 11 to 13 show another modification of the boundary layer control system in which the cylinder 50 remains untouched and an opening 490 is formed in the pylon 26 just rearwardly of the cylinder 50. Side plates 402 are faired to each side of the cylinder 50 and extend rearwardly to a point adjacent the rearrnost portion of hole 400. The side plates 492 curve inwardly at 404 and extend forwardly to the cylinder 50; This forms an opening 466 which permits air to pass to the opening 400. Opening 490 is connected to a conduit 408. This conduit can be connected to the inlet of a turbine engine or can be connected to a pump as in the modification shown in FIG. 8. A splitter plate 410 extends rearwardly from the cylinder 50 to a point just rearwardly of the opening formed by the side plates 402 where they curve inwardly.

It is to be understood that the invention is not limited to the specific description above or to the specific figures, but may be used in other ways Without departure from its spirit as defined by the following claims.

I claim:

1. In combination in an aircraft, a fuselage, a pylon positioned over and mounted on said fuselage, a rotor head mounted over said pylon for rotation, an enclosure member extending upwardly from the pylon to a point adjacent said rotor head, means directing a flow of air outwardly along each side of the enclosure member between the rotor head and said pylon, and pump means connected to said directing means for pumping a flow of fluid thereto.

2. In combination in an aircraft, a fuselage, a rotor head mounted thereon for rotation, a now-rotating enclosure member extending upwardly from the fuselage towards said rotor head, means directing a flow of air along each side of the enclosure member between the rotor head and fuselage, said directing means including a nozzle on each side of said enclosure having its outlet directed rearwardly, and pump means connected to said nozzles for directing a flow of fluid thereto.

3. In combination in an aircraft, a fuselage, a rotor head mounted thereon for rotation, a cylindrical member extending upwardly from the fuselage towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and fuselage, and pump means connected to said directing means for pumping a flow of fiuid thereto.

4. In combination in an aircraft, a rotor head mounted thereon for rotation, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, said directing means including a plurality of nozzles extending in a vertical line on each side of said cylinder, said nozzles having their outlets directed rearwardly, and pump means connected to said nozzles for directing a flow of fluid thereto.

5. In combination in an aircraft, a rotor head mounted thereon for rotation, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, said directing means including a plurality of nozzles extending in a vertical line on each side of said cylinder, said nozzles having their outlets directed rearwardly, and means for supplying a flow of gas to said nozzles, said last-named means including pump means connected to said nozzles for directing a flow of fluid thereto.

6. In combination in an aircraft, a rotor head mounted thereon for rotation, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, said directing means including a plurality of nozzles extending in a vertical line on each side of said cylinder, said nozzles having their outlets directed rearwardly, means for supplying a flow of gas to said nozzles, said supply means including a pump, and pilot operable means for controlling said pump to regulate the flow of gas to all of said nozzles.

7. In combination in an aircraft, a rotor head mounted thereon for rotation, a fairing on said rotor head mounted to tilt, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, and a telescoping afterbody extending rearwardly of said cylinder from a point on each side of said cylinder aft of said means directing a flow of air out each side.

8. In combination in an aircraft, a rotor head mounted thereon for rotation; a fairing on said rotor head mounted to tilt; a cylindrical member extending upwardly from the aircraft towards said rotor head; means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft; a telescoping afterbody exten-ding rearwardly of said cylinder from a point on each side of said cylinder aft of said means directing a flow of air out each side; said telescoping afterbody including a first fairing section fixed with respect to said cylinder and aircraft, a second fairing section comprising two plates, each plate being pivotally mounted to said first fair-ing section at the upper part of its rearward end, a third fairing section comprising two separate sides, each side being pivotally mounted to one plate of said second fairing section at the upper par-t of its forward end, and

spring means biasing said telescoping afterbody to an extended position to mate it with said fairing at all operating positions of said fairing.

9. In combination in an aircraft, a rotor head mounted thereon for rotation, a fairing on said rotor head mounted to tilt, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, said directing means including a plurality of nozzles extending in a vertical =line on each side of said cylinder, said nozzles having their outlets directed rearwardly, and a telescoping afterbody extending rearwardly of said cylinder from a point on each side of said cylinder aft of said line of nozzles.

10. In combination in an aircraft, a rotor head mounted thereon for rotation, a fairing on said rotor head mounted to tilt, a cylindrical member extending upwardly from the aircraft towards said rotor head, means directing a flow of air out each side of the cylindrical member between the rotor head and aircraft, said directing means including a plurality of nozzles extending in a vertical line on each side of said cylinder, said nozzles having their outlets directed rearwardly, and a telescoping afterb ody extending rearwardly of said cylinder from a point on each side of said cylinder aft of said line of nozzles, said afterbody being biased so that it extends between said aircraft and said fairing.

11. In combination in an aircraft, a rotor head mounted thereon for rotation, an enclosure member extending upwardly from the aircraft towards said rotor head, means directing a flow of air along each side of the enclosure member between the rotor head and aircraft, said directing means including a nozzle on each side of said enclosure having its outlet directed rearwardly, each outlet of said nozzles extending as a slot down each side of said enclosure, and pump means connected to said nozzles for directing a flow of fluid thereto.

12. In combination in an aircraft, a fuselage, a pylon mounted on said fuselage, a rotor head mounted over said pylon for rotation, an enclosure member extending upwardly from the pylon towards said rotor head, said enclosure being formed as a cylinder, cooperating means directing a flow of air along each side of the cylinder between the rotor head and aircraft, and an afterbody extending rearwardly of said cylinder from a point on each side of said cylinder located rearwardly of and adjacent the cooperating means directing a flow of air along each side of the cylinder.

13. A telescoping streamlined afterbody including a first fairing section fixed with respect to two fixed bodies to be faired, a second fairing section comprising two plates, each plate being pivotally mounted to said first fairing section at the upper part of its rearward end, a third fairing section comprising two separate sides, each side being pivotally mounted to one plate of said second fairing section at the upper part of its forward end, and

spring means for biasing said afterbody to an extended position.

References Cited in the file of this patent UNITED STATES PATENTS 2,369,652 Avery Feb. 20, 1945 2,453,721 Mercier Nov. 16, 1948 2,514,206 Perry July 4, 1950 2,653,779 Terry Sept. 29, 1953 2,699,833 Jensen Jan. 18, 1955 2,755,038 Gluhareff July 17, 1956 2,755,866 Apostolescu July 24, 1956 2,831,543 Matthews Apr. 22, 1958 2,841,344 Stroukoff July 1, 1958 2,974,904 Fielding et a1 Mar. 14, 1961 FOREIGN PATENTS 931,266 Germany Aug. 4, 1955 OTHER REFERENCES Aero Digest, issue of April 1, 1945, pp. 98, 99, 170. 

1. IN COMBINATION IN AN AIRCRAFT, A FUSELAGE, A PYLON POSITIONED OVER AND MOUNTED ON SAID FUSELAGE, A ROTOR HEAD MOUNTED OVER SAID PYLON FOR ROTATION, AN ENCLOSURE MEMBER EXTENDING UPWARDLY FROM THE PYLON TO A POINT ADJACENT SAID ROTOR HEAD, MEANS DIRECTING A FLOW OF AIR OUTWARDLY ALONG EACH SIDE OF THE ENCLOSURE MEMBER BETWEEN THE ROTOR HEAD AND SAID PYLON, AND PUMP MEANS CONNECTED TO SAID DIRECTING MEANS FOR PUMPING A FLOW OF FLUID THERETO. 